1118P Real-world adjuvant treatment patterns in patients with stage I-III EGFR-mutated non-small cell lung cancer (NSCLC) in China: Interim analysis from the ADDRESS study

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are recommended as adjuvant therapy for early stage EGFRm NSCLC patients. Our study aims to describe real-world adjuvant treatment patterns and subgroup analysis for patients with resected EGFRm NSCLC in China. Patients with resected EGFRm stage I-III NSCLC between July 2020 and October 2021 in 51 sites in China were enrolled. The endpoints are postoperative initial adjuvant and follow up treatment patterns and patient profile analysis among different adjuvant treatment patterns. Until data cut off on 8 October 2021, 1003 patients with stage I-III EGFRm NSCLC were enrolled, of which 914 were evaluable. Baseline characteristics: median age 59 y; 33.9%≥65 years; 34.9% female; 83.4% never smokers; 99.9% ECOG 0-1; 99.5% adenocarcinoma; 88.3% common EGFR mutation, 10.6% uncommon EGFR mutation. The majority of patients were stage IA (77.2%), while 22.8% were stage IB/II/III (12%/4.5%/6.3%). Across all patients, 222 (24.3%) patients received adjuvant therapy. 82.9% (184/222) of them received EGFR-TKIs, 10.8% (24/222) received chemotherapy, and 0.5% (1/222) received chemotherapy combining with EGFR-TKI. Among those received adjuvant EGFR-TKIs therapy, 87 (47.3%) patients received Osimertinib, 89 (48.4%) received the first-generation EGFR-TKIs. According to different clinical stage, 13.0% (86/662) with stage IA, 49.5% (51/103) with stage IB, 74.4% (29/39) with stage II, and 63.0% (34/54) with stage III received adjuvant therapy. This is the largest real-world study to observe the adjuvant treatment patterns of Chinese patients with resected I-IIIA EGFRm NSCLC until now. The data showed that the majority of patients who received radical resection were at a very early stage in the real-world setting. Adjuvant therapy increases with increasing clinical stage. In patients with stage IB-III, 58.2% received adjuvant therapy and only 36.8% of those with adjuvant therapy received adjuvant osimertinib. These results suggested that the adjuvant treatment rate and the use rate of oOsimertinib in stage IB-III still needs to be improved for the greatest benefit, especially stage IB.